discopotato03

Interesting thoughts Pro engines , I was told that propper pent roof compact combustion chambers with large quench pads as you say tend to work best . I'll have to dig up some pics of Cosworths designs ie DFV's and BDA's to refresh my memory . I do remember thinking FJ's have a nice chamber design . Have you seen pics of 5 valve chambers and some 4 valve types where the chambers close in from all sides to minimise the volume and as you say compress the mixture close to the plug for short flame paths and minimul end gas to detonate . When I fist looked at RB 4 valve heads I thought the step from the quench zone was pretty deep and wondered if decking them and using deeper dish pistons could help that low lift scavange phase . Cost aside I suppose the best way is mill the head and custom pistons though I'm not sure how thick the deck is on RB's and what is a reliable minimum . SK mentioned an 80 thou gasket and depending on if or by how much the crown came up in the gasket the quench zone gap (between pistons and head) may be reasonably small . The person whos views I follow said work on 25 to 40 thou which sounds the part to me . I would be interested to know what sort of stretch you allow for in a reasonably high reving RB ie 8000 so that the piston never gets to meet the head ! Cheers A .

Provided you use the real one and don't go any larger than necessary on turbine housing AR its a good start . The current one (real one) ATM doesn't have an integral wastegate . There is a .82 integral housing version in the pipe but its probably too big for an RB20 . If Garrett make an integral .63 AR version of the GT30 housing it would be pretty good on that turbo but don't expect boost off idle for a 270Kw RB20 . Cheers A .

I can't tell without seeing the bearing housing but the turbine looks like the pre ball bearing ceramic Hitachi . There should be a bolt head in one side of the bearing housing that may have been for bearing pre load adjustment . The BB type is "fatter" in the bearing housing than the plain bearing type . Cheers .

A laggy dog even if was genuine Garrett . People have to get it into their heads that bored out T3 housings while convienent do not work with TO4B/E compressor ends . Nissan used the small series T3 turbine and their own style of housing and waste gate . The USDM Ford/Garrett T3 turbine/housing/wastegate combo was different (larger) and has some chance of powering TO4E compressors because of this . ANY T3/TO4E hybrid is ancient history nowdays . Much better things are available . Don't confuse these things with Garretts TB31's and TA34's because while they can have some dimensional similarities they are not the same thing . They use more modern turbines and housings than any T3 though the GT series bits are a big jump beyond both .

Interesting about the HKS2535 turbo , they're supposed to use a compressor in between the 2530 (60mm) and 2871/GT-RS (71mm) . I think HKS blurb quotes 69mm 84T so probably the closest available compressor for the high performance GT28 turbine . If you can read the turbos ID tag may I have its numbers please . Also if you remove it some pics would be handy . Cheers A .

Searched , can't find that thread . Link ?

I guess theres pros and cons for doing it that way though it would possibly be simpler to retain the std manifold (water collector wise) and run some small bore lines to a header tank at the highest point to prevent buildup of steam pockets . Manufacturers go to a bit of trouble to make cooling systems work because if they don't the business fails . I agree that having inlet manifolds water heated helps with emissions ( and warm up , and cruise comsumption , and iceing) particularly at small openings but you can get around this to a degree with cooler thermostats if performance is the no 1 priority . Gary may have asked before but did the GMS cars use all std inlet manifold bits coolant wise ? Cheers A .

No , its how I got it .

I have a silver 84 model Iron Mask DR30RS with Volk 16x7 and 16x8 wheels . Is straight clean and runs all the original Nissan engine (inc electrics) gearbox and diff . Mods aside from wheels are some sort of Japanese cat back exhaust and Bilstein dampers . It also has a very comfortable Japanese aftermarket drivers seat . The only thing you may not like about it is its three button sprung centre clutch . Has been in HPI while in the hands of its former owner (B.E) . When I get a chance I'll get it out (lives in garage 99.9% of the time) and take some pics . Cheers A .

GTRGeoff I was thinking along the same lines , static pressure vs velocity pressure . Hugh Macinnes mentions in an early book on turbochargers that a static pressure probe is not affected by the velocity of the gas . By static probe he means tapping into a duct with air flowing through it at 90 deg to the direction of travel . A total pressure probe looks like an "L" shaped tube with its entry facing the approaching gas . Actually it makes me wonder how boost gauges and wastegate actuators would go if they worked off total pressure instead of static pressure . May be an interesting way of regulating the turbo/s at the point of the boost threshold to make the transition from atmospheric to positive inlet manifold pressure a bit more tightly controlled , better handle on torque surge and detonation at that point . Gone OT , sorry , out .

No it goes deeper than that . The compressor cover itself is of a higher AR ratio than Garretts and they have done a few sneaky mods (patiented) to the diffuser section of the housing itself . Notice how HKS don't have an AR ratio number cast into the covers on their TO4Z or T51R's . The drilled port shroud is probably bling factor though in small turbine housing form it may help a bit . No doubt HKS have used any tricks they could think of in the turbine housing as well . You may have noticed that their custom TO4Z and T51R housings are circular cross section in the volute passage , their web site claims that circular rather than oval shape does something to boundary layer flow . More uniform acceleration into the nozzle ? At least the TO4Z housing has a T4/TA45 flange rather than the T51R's circular V band setup . Damn you Cruiseliner , I really want to see the inside of the Z cover , still I'll have to rev up the spies OS . Cheers A PS I think I did see a pic of the HKS versions turbine with a slight back cut of the blades but unconfirmed . There were many conflicting claims that the HKS version used a slightly different or modded turbine . The fact that both versions use the same number cartridge would seem to prove otherwise . Out of time cheers A .

Over from the Wolf/PFC/Motec Autronic thread . I've always been interseted in the specifics of EFI evolution and what developed from motorsport than can benefit us on the street . My fist EFI setup was non factory using a now ancient Haltech E6 on an L series 4 . It was batch fire only so not very sophisticated but it worked reasonably well - compared to a pair of Webers . Electronics aside the batch injection I think was a simple way to get injectors of limited size to inject twice in the four stroke cycle . I was reading up on sequential injection but could not really get those around me to see any positives from it . To me it seemed logical to inject once and have some say in the injector close timing but the rally heads were not interested in low speed performance . They were saying that sequential needed larger injectors to get it all in with one burst and that the timing was not important . My next victim was an FJTurbo motor and an Autronic SMC which is sequential . After using the std injectors I convinced myself I needed larger ones and fitted modified Bosch (403) 500cc squirters . Luckily I knew someone else that had a similar spec engine so I had maps to a least make it run . I like my engines to idle well and be crisp at low speeds so I spent a lot of time mucking around with injection timing and ignition timing to get it to behave itself . My engine had no idle bypass motor/solenoid just the "dumbell" style valve with the electrically heated bi-metalic strip . I was saving the SMC's single PWM output for a boost control valve . Both of these engines were MAP load sensed . By the way I did prove that injection timing made very noticable differences to how well sequential injection runs . The SCM allows you to time the injection anywhere in the 720 deg cycle (360 x 2 for four stroke cycle) and from best to worst was quite a variation . Those injectors were probably similar to the Mazda RX5 T being large single pintel valve and I'm told more of a squirt than a spray . So this leads into injector types and from what I've seen many performance cars use high current or low resistance injectors of high flow capacity . I gather these need the resistor unit like GTR's and std FJ20's use but not being an electronics expert I'm not sure how that bit works . The other things I'd like to know about are the peak and hold vs saturated systems and about high performance read high speed injector drivers in the ECU itself . Now I havn't used a Wolf so I should not slag it but is the fact of the matter cost with boxes that don't support sequential injecton or motorsport standard injector drivers ? One would imagine that Apexi had a fair idea that we may be using giant - compared to std - injectors so their drivers would have to be to a high standard to cope . Some years back I found an article on what GM in the US did to their Gen 3 era ECU to make a competition version for their road racing Corvett . I think it was in Race Car Magazine and got lost somehow . If anyone has the article I'd like to read it again . Anyhow the ECU from memory was beefed up to take the heat and vibration plus mods to non std drivers and whatever the gadgets are that do the counting business for injection and ignition . I think whatever was driving the coils was beefed up too . Cheers A .

Hi all , I find this part of the topic most interesting but a new thread I think as its not specific to the Wolf ECU . Cheers .

Mazgtr , no the RB26 specific GT-SS's don't use the high performance GT28 turbine like the SR20 GT-SS does . In fact the 2510 and the RB26 GT-SS are probably the only Nissan specific GT25/28 HKS BB turbos that don't . When looking for specs check the turbine trim number , if it says 76T its most likely the good one . 2540's will always be laggy because even with the good GT28 turbine its still a 54mm turbine trying to drive a 76mm TO4E compressor . In todays terminology it would be a GT2876R but with a E series compressor rather than a 76mm GT37 wheel .

So if you paid half the price of the known quantity (PFC) and it ran half as well with poor consumption are you really better off ? Gary maybe you can tell me why there is resistance to using Hotwire Mass Air Sensors because I can't see any great disadvantage . Provided the bloody thing passes the air whats the issue ? Cheers ...

Cubes my understanding of the losses due to throttling is more relating to effective or dynamic compression ratio . Cylinder charging tends to be pretty poor with not much area to breathe through so with less air ingested there's less to compress so the dynamic compression ratio will be way down . Driving in a higher gear usually means the throttle will be opened further so cylinder charging will be better and dynamic CR higher . The system that has no throttle is actually throttled by the inlet valves so in theory it has no upstream restrictions . That system can do some amazing things to valve timing and lift like having no overlap at engine cranking and low speeds . You would be surprised just how much altering the valve open period and ignition timing variation affects dynamic compression . The next step is direct chamber injection because you can have more of the Diesel engines advantages like injecting very late in the compression stroke and cashing in on thermal efficiency . Naturally with this system fuel pressure is very high compared to port injection because fuel rail pressure has to be higher than compression pressure . The higher pressure makes for better fuel atomisation so in theory a more even fuel/air mix . I like to let an engine idle when started from stone cold (been standing overnight) for about a minute or two as I think combustion heat taking the chill off the piston crowns valves and chambers means less fuel hosed down its neck just to keep it firing - cold gun effect . A good friend once pointed out to me that if you drive an engine for torque it generally gives good consumption - this assumes its tuned and functioning properly . Cars these days have so many lounge room accessories its a wonder they don't have a rudder and screws . If people could live without the 6 stacker power windows A/C etc they would be much lighter and have better power to weight ratios . Depends on you priorities I suppose . I believe if you keep it light and the state of tune not too high its possible to have it both ways - the thing to keep in the normally used rev range is torque . Cheers .

Probably impossible but I'd like to know what the compressor and turbine flow rates are because that tells the story without giving away his specs . Sooner or later someone will buy one and whip the covers off for a seedy photo and measure session and then the cats out . There are limits to what can practically be fitted into the Hitachi's std housings so someones "XTR" type will probably be hard to beat . Rebuild costs ? If the wheels / centre housing/ turbine shaft are not damaged its a clean up kit and balance job . When the shaft and bearing housing are not reusable or need grinding its going out the door backwards . I agree with Gary , save for twice as long . The fact that Turbo X falls in like a standard one is a huge bonus . Cheers A .

Often the exhaust flow ceiling is the weakest link . It may sound silly but you could try lowering the boost to a point the turbo can live with and concentrate on tuning cam timing and the ECU itself to get the most from its air and fuel . My opinion only but many power graphs look like the side of Mt Everest and while riding the boost / torque wave may seem like a good idea remember that radial compressors have a useful speed range and the more pressure you ask of it the narrower the band will be . I'd be interested to know what sort of engine revs you have when the turbo cries enough . If its short of the engines std rev limit by a fair margin I'd try less boost and more revs . I'm only guessing but I think the 2835 series are a bit compromised by their 56.6mm turbine , I think it was done to give a bit of low to medium range response at the expense of the very top end . Its very difficult to have it both ways . This is why I keep harping about the benefits of generous turbine and housing capacity and using compressors of adequate capacity and no more . I did mention that Garretts propper GT3071R uses the largest 71mm 56 trim compressor with the full sized or 60mm GT30 turbine . Garretts long overdue T3 flanged integral gate GT30 turbine housings should be available in late July and one of these with the GT3071R should do 300Kw (400Hp) because it has the gas flow capacity on both sides of the turbo . The word is that these T3 flanged housings will be in .82AR ratio so may not thump you in the back at 2500 rpm but should be very controllable . The RB25DET's having 9.5CR (or is it 9.0) would like a turbo that doesn't boost off the starter motor and give the opportunity to screw some advance into it before the boost threshold . I think I'd be finding out what sort of money you could turn your turbo into and what the dough could buy that worked better . One thing I don't understand is you say you have a spare ".86 Pro S " housing , if T3 flanged it should be .68 or .87AR ratio . If its .64 or 86 it would be a T28 flanged GT28 housing . Since you mentioned GCG I would be talking to Brett about my above suggestion . Some of the more recent GT BB turbos are going the healthy turbine medium compressor route and it can pay off if its efficient airflow your after rather than high boost numbers . Cheers A .

Ok , the 90 trim cropped 2835 style turbine probably won't make enough of a difference to bother with though this and or the .87AR ratio 2835 Pro S housing are the last steps for that family of turbos . After them the next turbine/turbo family is the GT30 series meaning the full sized or 60 x 55mm 84 trim UHP turbine . They are available with 71 , 76 and 82mm compressor families (GT35 , GT37 and 82mm GT40) series compressors . Examples would be Garretts GT3071R , GT3076R and GT3040R . If you just wanted to uncork the turbine side the GT3071R could be used as its basically the same deal but with the non cropped turbine . These will fit into the GT3037's Pro S type turbine housing . If you want more compressor flow then the 76mm GT37 compressors can do it and probably get close to 500Hp depending on compressor trim and turbine housing AR ratio . The options are Garretts GT3076R unit no 700382-12 or HKS's GT3037 of which there is a Pro S version using the same cartridge and wheels as Garretts GT3076R - identical cartridge (CHRA) pt no 700177-7 . Just on those Pro S exhaust housings , I'm not certain that the 2835 and 3037 versions use the same castings even though the AR ratios are the same - .68 and .87 . If you look at the outlet side of your 2835 pro housing you'll see how thin the casting is in the area between the turbines outlet and the scolloped out section venting from the wastegate flat valve . Its hard to imagine there being enough room for the 84 trim GT30 turbines 55 and a bit mm outlet to fit without "daylighting" the casting between turbine and wastegate outlet paths . If I could not be certain I'd be hesitant to machine it out for a GT30 turbine as these housings are not cheap to buy . If your not happy with the 2835 Pro it may be a better idea to sell it complete and buy the turbo you want . The burning questions are always what mounting flange and integral or external wastegate . If you are seriously going to push the power envelope a better than std exhaust manifold is probably needed and HKS do a good one for the RB20/25 . External gates always remove the exhaust housing dramas and make it easier to get the hot side working properly - in a high power setup . Basically the sky is the limit , only you know how much you want to spend and how incognito you want it to be . I don't think I would go beyond a 3037 Pro on the std manifold or a GT3076R (basically non gated Garrett equal) on the HKS manifold . At this stage many feel they are losing the lower mid range where its important for a street car to work well . I wouldn't bother with a GT3040R , the large trim GT37 compressor (3076R/3037) is already beginning to overstretch the GT30 turbine so going bigger again to the 82mm GT40 I think is a step backwards . An almost 500 Hp turbine is not suited to driving a 700 + Hp compressor IMO . Lets know what you think , Cheers A .

Grepin a couple of cause and effect issues here and some unit number information for others . It looks like you've run your GT2835 Pro S beyond what its designed to cope with air and exhaust flow wise . High turbine inlet pressure is what's forcing your integral waste gate flat valve open . Wastegates are generally regulated by boost pressure so if you factor this plus the actuator spring rate and lever ratios of the linkage + arm the turbine inlet or exhaust manifold backpressure if you like must be pretty high . From the HKS spec sheet I have it seems the 2835 Pro in RB20/25 version ie having the T3 flanged turbine housing uses that cropped GT30 turbine ie 56.6mm diametre in 84 trim only . It shows the T28 flanged version (bored out .86 AR ratio GT28 turbine housing) as using the 90 trim version of the cropped 56.6mm turbine . Also the GT Pro 2835 uses the largest trim version of the GT35 compressor ie 71mm 56 trim . I should start from the base line with the 2835 series turbos or it gets confusing . They are offered in five versions and four power ratings ie 380 , 400 , 410 and 420 PS . The straight 2835 can have three compressor trim options - 48 , 52 and 56 . These three have the same turbine and trim - 56.6mm 84 trim (51.8mm exducer or outlet diametre) . They can have the GT28 integral gate exhaust housing in .64 or .86 AR ratios . Or they can have the GT28 flanged external gate GT30 housings in .61 , .73 , .87 , 1.01 and 1.12 AR ratio . The next step up is the Pro version with 84 trim turbine for T3 flanged Skylines or 90 trim for GT28 housings for SR20/CA18 etc . Remember 56 trim compressor . Last type is the GT2835R which gets the 90 trim turbine and 56 trim compressor standard . It can have the 86 AR ratio GT28 exhaust housing or the T28 flanged GT30 housing in 61, 73 , 87 , 1.01 and 1.12 AR ratio . Anyhow your GT Pro version probably hasn't got the 90 trim version of that turbine which is only 1.8mm larger in exducer diametre at 53.6mm . There are a few ways you can go depending on what result you want to end up with . I have to dash ATM but will get back on this later on , Cheers Adrian . HKS_GT2835_Pro_S_.67_ARR_housing.bmp

Gwan , show em the compressor wheel !

Will have to ask Fred and Brett next time I see them . Both the GT30R/GT3076R and the 56T GT3037 use the same identical compressor and turbine . Turbobygarrett list its unit and CHRA numbers and these are pics of the HKS GT3037 version . Compressor is the 76.2mm 56 trim BCI-18C family also known as GT37 series hence GT30 37 . 56 comp trim CHRA is 700177-7 . 52 comp trim CHRA is 700177-6 . Pretty sure 48T version is -5 . Its interesting to note that HKS rate the power potential of the three trim sizes at 470 , 440 and 420 PS , they also rate their largest comp trim version of the GT2835 ® version as 420 as well . Compared to Garretts their numbers are conservative as has been said before . The jump from 440 to 470 is big but not unusual for a 2mm rise in inducer size . Its asking a lot for the GT30 turbine to power these compressors much past this sort of level let alone pass the exhaust gas to allow it . To me it says go the 52 trim or use a larger family turbo for greater power output . For better response the right 3071R uses the right turbine with the right compressor and dosen't have the all expensive High Kost Spec tag . I agree with the propper Garrett .63 GT30 exhaust housing it should work quite well , if an RB20 can get it on at 3000 a 25 should be better again . Nite all ..

As far as I know the lowest propper GT30 turbine housing AR ratio is .61 made for HKS , Garretts lowest is .63AR ratio . Are you sure the .48 is not a bored out T3/TA or TB housing ? All of Garretts and HKS's housings have the conical stand off style outlet 4 bolt set up - Pro S housings aside . I have seen some being sold in the US with the housings outlet virtually flush but these are not GT30 housings .

From a cartridge point of view yes the Garrett GT30R/GT3076R is the same as HKS's GT3037 in 56 compressor trim just make sure it has the part numbers mentioned above . There is a bit of a grey area with HKS's GT3037 because it can be had with 48 52 or 56 trim compressors of the 76mm diametre GT family . I've never seen the 48 trim version but the 52 trim one is around though not as common as the 56 trim version . In the US the SR20 is quite popular and they seem to work well with the 52 trim GT3037 and HKS's .73 AR ratio exhaust housing . They claim that the 56 comp trim version's boost threshold is about 5-600 RPM higher than the 52 trim one which is worth noting . It's a shame that HKS don't offer the 3037 in 52 comp trim with the Pro S versions integral wastegate exhaust housing . The slightly smaller wheel trim makes all the difference from a turbo response perspective . Many have found that the Garrett version (GT30R which is essentially a 3037 56T) to be a bit laggy which is not surprising when you look at its compressor and turbine diametres and flow maps . I would be holding out for the 52T version if it had to be a 3037 , you can achieve the same thing airflow wise with the right Garrett GT3071R - it uses a smaller 71mm (vs 76mm) GT compressor but in 56 trim (same comp wheel as HKS GT2835 56T) in the same style of comp cover as the 3037 52T . To my way of thinking that GT3071R is good because it uses the same turbine as the 3037 range with the compressor wheel from the larger trim 2835 . The really critical thing is getting the turbine housing AR ratio right with the GT3071R and I'd say HKS picked the right numbers ie .68 and .87 for their Pro S integral gate T3 flanged GT30 exhaust housings . The 68 would be nice on the street and should give a good spread of power provided you don't ask it for 40 lbs boost . The .87 would better suit the 3037 in 56 trim if you don't mind it motorvating a bit higher up the rev range . Its not a good idea to put smaller AR turbine housings on turbos with large big trim compressors because they tend to make the turbo surge in the spool up phase and choke the exhaust side up high - dumb really . GT30Rs/3037's can be good things but the right versions may not be a cheap easy solution - depends on how much you can do yourself and how much munjaras you have to spend . More than one punter has pulled them off because the lag factor was unacceptable so choose conservatively which compressor version to use . Its very much a case of least is best in a daily driver .

R334DR if that link to HPIB was correct that turbo IS NOT a propper GT30R . It is a Garrett hybrid GT30/TO4S meaning it has the dinosaur 7/14 blade TO4S compressor instead of the 76mm GT 6/12 blade compressor . If you want the propper GT30R its part no is 700382-12 , cartridge no 700177-0007 or -5007 . Most HKS GT3037's use this same cartridge but it is available from them in 52 and 48 compressor trim . Most who have them like the HKS GT2835 Pro S but you can also get a HKS GT3037 Pro S integrally gated turbo . HKS don't sell the dodgy GT30/TO4S option because they know its a laggy dog . HKS also go to a lot of trouble to supply ALL the bits to make their turbo kits bolt on . The Pro S exhaust housings are amongst the best high performance integral wastegate types available . If it were up to me I'd say 2835 pro or 3037 pro depending on how much lag your prepared to live with . At that power level a very obviously non standard engine bay and external gate are hard to justify . Very expensive setback if defected and no cops gonna miss it . Your call .